Topical Gardening Tips
Question: I love parsley, and I have heard that it can be sown in fall and grown through winter. Are there any special things I need to do to make this project successful in my Zone 6 garden?
Answer:Most gardeners grow parsley (Petroselinum crispum) as an annual, but it actually is a hardy biennial. Parsley’s natural life cycle is to germinate in late summer, persist as a seedling through winter, and then produce flowers and seeds the following spring. It will follow this natural rhythm in a garden quite easily if you help the seeds to germinate promptly — and then provide the plants with protection to buffer them from the ravages of winter.
Of the two types of parsley most often used — curly parsley and flat-leafed Italian parsley — curly parsley leaves have a higher dry-matter content, so they withstand freezing weather a little better than Italian parsley, which has juicier leaves. All types of parsley are generally rated as hardy to Zone 5 or 6, but I think the curled varieties are best for growing from fall to spring.
Late summer to early fall is the ideal time to sow parsley seeds, which have a well-deserved reputation for germinating slowly. In more superstitious times, parsley seeds were believed to travel to hell and back several times before they would sprout. Virgins were not to sow them lest they risk impregnation by the devil — this despite the fact that early Christians consecrated parsley to St. Peter, keeper of heaven’s gates.
A FEW LIGHT FROSTS ARE GOOD FOR PARSLEY, BECAUSE THEY TRIGGER THE PLANTS TO ALTER THEIR LEAF CHEMISTRY IN PREPARATION FOR COLDER WEATHER TO COME.
Modern science has found an explanation for parsley seeds’ erratic germination. Parsley seedcoats contain furanocoumarins, natural herbicides that help parsley claim its space. These chemicals also inhibit the germination of parsley seeds, but it’s still an ingen-ious setup. After the furanocoumarins have leached out and temporarily suppressed the germination of nearby weed seeds, the parsley seeds finally sprout and start to grow.
Gardeners would prefer that parsley seeds go ahead and sprout, and one often hears various ways to enhance germination. Last year, I put three of these methods to the test. After dividing seeds from a fresh packet into groups of 20, I froze one group in a wet paper towel, froze another dry, and set another group to soak in room-temperature water. The next day I planted all the seeds in adjoining rows, including a fourth row of seeds sown dry from the packet. The results? Three weeks later, all four groups showed a 50 percent germination rate, with a few more seedlings in the row planted straight from the packet.
More intensive soaking and rinsing may be a better strategy. Lots of soaking and rinsing is exactly what seeds get when you repeatedly water the seeded bed, which keeps the soil cool and moist (parsley germinates best at 60 to 75 degrees), and gradually rinses away the furanocoumarins. Once the seedlings are up and growing, there is nothing more to do beyond thinning them to 8 inches apart, and pulling weeds until freezing weather is expected.
A few light frosts are good for parsley, because frost triggers the plants to alter their leaf chemistry in preparation for colder weather to come. But after the plants have hardened themselves to cold, it is best to protect them with an appropriate cover from Zone 7 northward. If you have several plants growing in a row, you can cover them with a plastic tunnel held aloft with wire hoops, with the ends left open for ventilation. Or place several stakes along the outside of both sides of the row and wrap a 12-inch-high band of clear plastic around the stakes to form an open-topped opaque cage. Protect individual plants with cloches made from plastic milk jugs with the bottoms removed. If you cut a slit in the top of the handle, you can push a stick through the handle and into the soil, which will help keep the cloches from blowing away. I protect my winter parsley with milk jugs and surround the installed cloches with a thick blanket of mulch.
All of these protective devices block cold winds and keep the plants’ roots on the dry side, which limits the risk of rotting in cold soil. An insulating blanket of snow is good for parsley, but in years with little or no snow, you can throw an old blanket over the cloched plants during periods when temperatures drop into the single digits.
Remove the plants’ covers as soon as the weather begins to warm in early spring. Trim off any yellowed leaves, but don’t give up on plants that appear to be dead. New stems will quickly emerge as soil temperatures rise, and they will have a remarkably sweet flavor, a byproduct of their exposure to winter’s cold. They will bloom in early summer, so plant replacements in spring to make sure you have plenty of parsley all summer long.
Barbara Pleasant plants parsley twice a year in her North Carolina garden.